UPSC Prelims is close, the competition is tight, and the stakes have never been higher.

As you already know, in UPSC Prelims, even a fraction of a mark could get you past the cut-off or leave you omitted from the result list.


prelims  answering strategies

Blind guesswork is sure to lead to failure because you lose 1/3rd mark for every wrong answer in UPSC Prelims.

Remember that there are 4 options for every answer so the probability of one being correct is 1/4. In other words, the probability of being correct by blind guesswork is 25%. With 75% probability of being wrong.

Suppose you do get the right answer, you end up gaining 1 mark (+1).

But the penalty of wrong answer is costlier with negative marking. With every incorrect answer, not only will you lose the 1 mark which you would have achieved with the right answer, you will lose an additional 1/3rd mark from your total score. So, your total loss for every wrong answer is actually (-1.33).


What can you do to push your score higher? Apart from acquiring more knowledge and studying harder there seem to be no other options. But this is where you would be wrong. You can push your score higher by a considerable margin WITHOUT any extra effort by using a MCQ-answering mechanism detailed in this Cheat-Sheet.

This can be done by exploiting certain biases in standardized tests like the UPSC Prelims , as revealed by the brilliant book by William Poundstone-Rock breaks scissors.



Every test has weaknesses and biases which the test-makers may remain ignorant of. Research now reveals that MCQ tests have certain patterns in the answer-patterns which get embedded subconsciously in the test by test-makers. Knowing and exploiting these patterns can make a difference of 5-15% in your score which, in the UPSC Exam is an ENORMOUS advantage to have over your competitors.

This cheat-sheet is the ultimate compilation of research-backed meta-hacks for attempting MCQ tests, esp. the UPSC Prelims 2021 exam while considering negative marking .

Video tutorial with explanation is here–


You will do 2 iterations or rounds of the Question paper.

Round 1

Eliminate as many answer-options from the other questions as possible.

Do not do any guesswork in this round.

Complete this round in 45 minutes or less.


Round 2

Now, Mark all answer-options which you are 100% sure are correct.

It is better to do so in the 2nd round because research suggests that accuracy of test-takers in MCQ tests improve drastically if they revisit their answer choices.

It will also minimize the possibility of a silly mistake or an impulsive decision. It requires patience to consider all 4 choices carefully and with the time and anxiety, you are very likely to commit avoidable mistakes. 

In Round 2, attempt ONLY questions in which you have eliminated at least one option. (This includes all the questions in which either three or two possible correct answers remains). However, do not attempt a question in which all 4 answer-options are open.


Use the following strategies-


  • Attempt ALL questions in which you have eliminated at least one answer-option. By doing so, you will push the statistical needle in your favour. Because while you may get some questions wrong, but overall, you will have gained additional marks.


  • Answer-options with absolute extremes never, none, always etc are likely to be wrong choices. Eliminate these from the remaining answer-options.


  • However, answer-options like ” none of the above” and “all of the above” were wildly more likely to be correct. Vote for these by adding a tick mark in front of these answer-options. Choosing these answer-options can lead to a 90% improvement over random guessing.


  • In a four-option test, the option most likely to be correct is (B). A perfectly random test should have a 25% chance each of A, B, C or D to be correct. But the data suggests that B is likely to be correct 28% of the time. If (B) is open, vote for it by adding a tiny checkmark on the question paper. This strategy alone can lead to an 11% improvement over random guessing.


  • In four-choice tests, chances that the same answer (A, B, C or D) will be repeated is 19% instead of 25%. This means that if the answer to a previous question is (D), then it is unlikely that (D) will be repeated as the correct answer in the next question. Use this to eliminate answers-options. This strategy can lead to at 8% or more improvement over random guessing. This can also be used if you know the answer to the next question in much the same way. The simple thumb rule is that Correct answers are less likely to be repeated.


upsc prelims cheat sheet 2021
Source : Rock breaks scissors by William Poundstone


  • The answer-option with the longest word-length is more likely to be correct. Test makers must make sure that the correct answer is indisputably correct and this often, requires more words to clarify and qualify the statement. Test-makers may not make the same effort with wrong choices.


  • Mark all the questions in your OMR sheet using the above strategies.


Here are the effectiveness rates of improvements of the above strategies over random guessing-


upsc prelims cheat sheet 2021
Source : Rock breaks scissors by William Poundstone




  • Proceed only if one or more option-answer have been eliminated.
  • Attempt ALL such questions.
  • Check if there are ‘none of the above’ or ‘all of the above’ answers. If yes, vote by placing a small tick-mark on top of it in the Question Paper.
  • Check if you know the correct answer to the question before or after the question you are considering. Vote down on these choices your target question by putting a tiny cross ×  over the answer-option. Put a small tick on the rest of the options which are still open. Avoid repeating answers.
upsc prelims 2021 cheat sheet
Source : Rock breaks scissors by William Poundstone
  • Check to see if (B) is still open. If yes, vote by putting a tiny checkmark on it in the question paper.
  • Choose the option with the highest votes.
  • In case of a tie, consider to pick the one with the longer word length.
  • In case the choices are too close and you have an intuition about one choice being the right choice, go with your gut. 


This has been tested by quite a few students of mine with good results. Some of them has reported an increase of 10 marks or more after using these techniques. While this may not sound like much, remember that these additional marks are absolutely FREE. They did not need to invest any study or hard work to get this boost in score.


It was pure bonus.




Why this additional bonus is so much more valuable than you might think is because in order for you to achieve a considerable jump in your score organically, you will have to expand your knowledge EXPONENTIALLY more than it is now. So, if it took 6 months to reach you current score level, it may take you more than 12 more months of additional work to achieve an even marginal increase in score. It gets harder and harder to increase the score after reaching a certain level.


upsc aspirant


This is why unfortunately, many people are unable to clear the Prelims year after year and remain hovering near the cut-off.


Important: Remember that knowledge trumps guessing always. These techniques will definitely help in pushing up your score and are much better than random guessing.


But you should not expect to clear the Prelims without having studied hard and acquiring knowledge.


So get to work!


Ravi Kapoor IRS


Author of the Ultimate Cheatbook of Essay & Answer-writing.




  • The Source of these insights and all the data in this article is the book by William Poundstone-Rock breaks scissors.
  • Before deciding to use them in the UPSC Prelims exam, you should practice using these techniques a few times . If you have joined a test series, you should observe and check for yourself, if these techniques are leading to an improvement in your scores and if so, to what extent.


  1. Sir, this is certainly insightful. However, I have my doubts about the random selection of “all of the above” or “none of the above” options as I used to do that, but examiners have started to put that option to confuse us even more. Also, while giving some entrance exams I saw that many times the correct answers were the same option as the previous one.

  2. Thank you very much Sir 🙏 It is very helpful I will surely apply it🙏 I was not aware about these technique before but as you explain that probability of correctness of option B between option C and D it is absolutely true because I also used it when I was a teacher in a school.🙏

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